The present invention relates generally to the provision of closed captioning for television and other audiovisual programming. In particular, the present invention provides advanced closed caption features using existing closed caption information carried in the television signal. The invention allows a user to override the closed caption presentation format as selected by the originator (e.g., programmer or broadcaster), in order to select alternate presentation attributes based on the user's preference. User customizable advanced closed caption features are provided, such as font size, font type, font color, caption window position, caption window size, print direction, scroll direction, scroll rate, text opacity, background opacity, text justification left, text justification right, text justification center, background color, and the like.
Closed captions are captions that are hidden in the video signal. Recovery of closed captions for display along with the television programming requires a closed caption decoder to be used in connection with the television receiver.
Beginning around 1980, closed captioning of video programs in the United States utilized Line 21 of the Vertical Blanking Interval (VBI) of a National Television Standards Committee (NTSC) television signal to carry closed caption data. In 1990, Congress passed the TV Decoder Circuitry Act, which required closed caption decoders in most television receivers. The TV Decoder Circuitry Act required the Federal Communications Commission (FCC) to produce standards for closed caption decoders. The FCC, with assistance from the Electronic Industries Association (EIA) Television Data Systems Subcommittee, has developed certain standards for the delivery of closed captions, including the EIA-608 and the EIA-708 standards. One technique for communicating VBI data, such as closed captions, in digital television data streams is disclosed in commonly assigned U.S. Pat. No. 5,844,615, entitled Communication of VBI Data in Digital Television Data Streams, incorporated herein by reference.
The EIA-608 standard, developed in 1991, is based on the Line 21 system and utilizes the DVS-157 standard for carriage format of the EIA-608 captions in digital cable systems. DVS-157 is a standard that has been established for the cable industry by the Digital Video Subcommittee (DVS) of the Society of Cable Telecommunications Engineers (“SCTE”). The EIA-608 closed captions are provided in a single, unalterable configuration.
The EIA-708 standard is a new standard which was developed in recent years and which utilizes the carriage format specified in the Advanced Television System Committee's (ATSC) A/53 standard for digital video. The EIA-708 standard is meant to provide “advanced” closed caption features in digital television signals at the Closed Captioning origination device. The EIA-708 “advanced” features include, but are not limited to, the ability to change certain closed caption features, such as the location of the closed caption display, and the size and color of the closed caption text.
The A/53 format used by the EIA-708 standard is not backward compatible with existing digital cable systems. Millions of existing set-top terminals currently in use by consumers support the EIA-608 standard carried digitally in DVS-157. These set-top terminals are incapable of being upgraded to accommodate the A/53 format utilized in the EIA-708 standard. Replacing the existing set-top terminals with EIA-708 compatible systems would be costly to consumers and operators alike.